The Hidden Depths Add-on for Minecraft Dungeons has 8 achievements worth 190 gamerscore.
Defeat 10 mobs with a single Trident explosion.
Return the lost conduit to its rightful place.
Kill a Glow Squid using an Ice Wand.
Hit each type of underwater mob with the fishing rod.
Complete the Radiant Ravine secret mission on any Apocalypse Plus difficulty.
Complete Abyssal Monument on Apocalypse difficulty.
Using the Bubble Bow, have 10 mobs bubbled at the same time.
Survive without oxygen for 60 seconds.